Over the course of the 20th century, the car became America's dominant mode of transportation. As vehicle miles travelled soared well past the rate of population growth, demands on the roadway surged. Congestion became a major issue. So transportation planners made the roads wider and added traffic lanes. Today, we now know that bigger roads and extra traffic lanes do nothing to solve congestion. In fact, it tends to induce even more traffic. So we didn't fix the congestion issues, and on top of that, we built wide roads that are relatively unsafe. Transportation planners in the 21st century recognized that many of the roads that were overbuilt could be redesigned to calm speeding and add space for newer multimodal transportation options. And thus, the road diet was born.